David Sibley has been putting up some interesting posts on bird ranges and migration based on banding recoveries. His latest post looks into the migration patterns of different subspecies of White-crowned Sparrows and questions the occurence of Gamble’s White-crowned Sparrow in the northeast based on information from recoveries. Follow the link below to read his whole post.
adult Eastern White-crowned Sparrow
White-crowned Sparrow subspecies – Where? by David A. Sibley
There are five subspecies of White-crowned Sparrow, and in most parts of North America it is possible to see more than one subspecies during part of the year. Identification of subspecies is covered in the Sibley Guide to Birds and in Dunn et al. 1995. Maps of band recoveries (from the Canadian Atlas of Bird Banding) offer insight into, and raise questions about, two of these identification challenges: separating the two dark-lored subspecies, Mountain West vs. Eastern, and distinguishing Gambel’s (Western Taiga) birds among Eastern Taiga birds in the eastern states.
